Several posters (including one extremely knowledgeable one) have weighed in on whether the ADA would require WDW to make an exception to the mask requirement for the disabled/those with special needs. The consensus is no because it would not be a reasonable accommodation where a contagious disease is involved.
Even though I don't think the disabled/special needs community is entitled to a mask exemption, I probably wouldn't label them selfish for asking. They're so used to the word that it probably wouldn't make an impact. All of the accommodations we consider commonplace now (accessible buses, wheelchair ramps, special education classes, etc.) were bitterly challenged as selfish when first proposed. I remember reading several editorials on how the "selfish" disabled were having seats removed from buses to the detriment of elderly customers more likely to use them. I'm not saying it's the same thing, just something to consider.
Lawyers don't make the laws, although they do file cases on behalf of people who want to test the limits of those laws. They also defend serial killers despite overwhelming evidence of guilt. That kind of goes along with the job. It's our legal system, like it or not. That doesn't, in itself, make them selfish or morally deficient.
As far as the airplane example, the overwhelming majority of people in this country do not have Covid.
This kind of hyperbole adds nothing to the discussion.